The present invention generally relates to sensing systems and, more particularly, to non-contact sensing systems.
Sensing systems are employed for a wide variety of purposes and in diverse fields. There are sensing systems for detecting motion, surface irregularities, environmental conditions, and for physiological conditions, to name a few. Applications can be used in such industries as medical, process, aeronautical, and others. Such diversity in purpose and industry results in a multitude of considerations for the designer or user of the sensing system. These considerations include cost, precision, measurement range, durability, maintenance requirements, and even the physical characteristics of the sensed object, among others.
Non-contact, or non-invasive, sensing systems are sensing systems that, unlike direct contact sensing systems, do not require the sensing portion (e.g. sensor) to physically contact (directly or through an intermediary) the sensed, or targeted object. Non-contact sensing systems offer many advantages over traditional direct contact sensing systems, such as the ability to provide information regarding an object and/or condition of interest without expensive and invasive sensor mounting assemblies. Non-contact systems, unlike contact systems, also have the advantage of not changing the system they are measuring. Radar systems are an example of one non-invasive sensing system. Radar systems use reflected radio waves, typically on the order of 0.9-100 giga hertz (GHz) to determine the presence, location, and speed of sensed objects. Some radar systems operate by transmitting either a constant continuous wave (CW) signal or a pulsed signal. Most of these CW radar systems operate under the principle of the Doppler effect, which is the change in received signal frequency with respect to transmitted signal frequency, due to motion. CW radar systems using the Doppler effect provide a mechanism of detecting a moving target by transmitting microwaves at a targeted object and detecting the change in frequency of microwave signals reflected from the target. Continuous wave radar techniques are non-contact, relatively inexpensive, and provide a sensing mechanism that is relatively unaffected by dust, debris, rain, and many other obscurants when the proper transmit frequencies are used. Conventional radar sensing systems provide limited information on the speed, location, and direction of movement of targets being sensed, but are unable to provide high resolution information of xe2x80x9csensed objectsxe2x80x9d on the subwavelength scale. Thus, there exists a need for a radar sensing system that improves the information received about the sensed target.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.
The present invention provides, among other things, a sensing system. The sensing system can generally be described as including, among other things, a transceiver device configured to transmit a signal toward an object, a plurality of detectors offset in phase to receive the transmitted signal and a reflected signal, and a processor configured with logic to measure a phase shift resulting from the relative motion of the object between the transmitted signal and the reflected signal at the plurality of detectors, wherein the processor is further configured with the logic to relate the phase shift to the relative motion of the object.
The present invention can also be viewed as, among other things, a sensing method. The method can generally be viewed as including the following steps: measuring a phase shift resulting from the relative motion of an object between a transmitted signal and a reflected signal at a plurality of detectors; and relating the phase shift to the relative motion of the object.
Other systems, methods, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.